I have the pre 2011 UDP but because I never turned on hotspot back then they won't let me now. Even then activating it would have cost a not insignificant additional $30 a month! The smart move is to turn it on for a day for literally a dollar then shut it off the next. Unfortunately not a choice for me now. Those who DID turn it on years ago got to keep it.
My plan is still cheaper than new plan due to discounts that are no longer available
Do you get high speed hotspot with prepaid Go? I could go that route. I always pay up front for phones.